1. Field of the Invention
The present invention relates to a parachute canopy of the type which comprises at least one steering or air passage aperture which is normally retained in a closed position by air pressure within the expanded canopy and which aperture is selectively opened to permit air passage therethrough by means of operating members such as pull lines which are controlled by a parachutist.
2. History of the Prior Art
Conventional completely closed parachute canopies have no apertures therein to control the direction of descent of the parachute, however, such closed canopies have the advantages of being quickly activated or deployed as they are rapidly filled with and retain air. Such parachutes thus afford safe deployment and require little vertical drop before becoming operative. These parachutes, therefore, are usually used for rescue and paratroop purposes.
In certain situations, it would be advantageous for the user of a parachute to be able to manipulate the chute or steer it during descent. The capability of maneuvering the parachute during descent makes it possible to avoid possible mid-air collisions with other parachutists as well as to avoid obstacles on the ground. In order to make parachutes more maneuverable, some conventional parachutes have been designed so that the shape of the parachute may be changed during descent to affect a steering of the chute. In other types of parachutes, steering is accomplished by altering the effective air pressures around the parachute by placing openings in the canopy which create a steering effect forcing the chute in a particular direction. In order to control the amount of air flow through such openings, prior art parachutes are provided with means for reducing the size of the openings during descent. Such reduction in the size of the openings is usually affected by the parachutist through the use of pull lines which extend from an area adjacent the opening to the parachute harness.
A drawback encountered with the use of conventional parachutes having openings therein which are used to control steering of the parachute during descent is that often such parachutes descend at a faster rate. For inexperienced jumpers the use of parachutes having steering openings therein may present an increased safety risk as the user of the parachute may not be familiar nor comfortable with controlling the amount of air flow through such openings to affectuate the proper movement of the chute as it descends. In paratrooping operations, experience has taught that there are increased risks of collision between parachutists immediately after the jump is initiated when steerable parachutes of conventional design have been used as the chutes have a tendency to be driven against one another before control thereof is established by the paratroopers. In addition to the foregoing, there is increased risk of collision between parachutists using steerable parachutes when jumping in darkness as the parachutists have difficulty in seeing one another in time to make the appropriate adjustment to the chute to prevent a collision.